Chu or CHU may refer to: Chinese history Chu (state) (c. 1030 BC–223 BC), a state during the Zhou dynasty Western Chu (206 BC–202 BC), a state founded and ruled by Xiang Yu Chu Kingdom (Han dynast
1. Compute SHA-256 of OTSCanonicalRecord value → must equal OTSHash 2. Open OTSProofURL → extract Bitcoin block number → must equal OTSBitcoinBlock 3. GET OTSBitcoinBlockVerifyURL → returns the Bitcoin block hash at height OTSBitcoinBlock; GET https://blockstream.info/api/block/{that hash} → its timestamp must match OTSTimestamp 4. Read CopyrightID inside OTSCanonicalRecord → must equal the CopyrightID above 5. GET OTSVerificationAPI → pre-computed 6-check result from server 6. If all match: this entity was registered on CopyrightChains at OTSTimestamp, independently verifiable on Bitcoin Note: an OTS proof may carry multiple Bitcoin attestations; OTSBitcoinBlock is the earliest confirmed one — a later attestation inside the proof corroborates it and is not a mismatch
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd5b1166fdd6d9cee829642c168fda6c22438d3b77315fb5ee9c886ab180c218e. Chain 2 (Bitcoin): anchored in block 953803 (2026-06-15T15:41:00Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/e5beceab-6099-49ee-9bff-91f792f5b3d6.json and https://artists.proofprofile.net/proofs/artist/e5beceab-6099-49ee-9bff-91f792f5b3d6.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
1. Confirm isrcCode identifies the recording in the pre-2022 source corpus and cc-db-prod record 2. GET OTSVerificationAPI → server-side canonical-record, hash, and attestation checks must pass 3. GET OTSBitcoinBlockVerifyURL → returns the Bitcoin block hash at height OTSBitcoinBlock; GET https://blockstream.info/api/block/{that hash} → its timestamp must match OTSTimestamp 4. Confirm CopyrightID is the CopyrightChains transaction hash 5. If all match: the cc-db-prod record is independently anchored on Bitcoin at OTSTimestamp Note: an OTS proof may carry multiple Bitcoin attestations; OTSBitcoinBlock is the earliest confirmed one — a later attestation inside the proof corroborates it and is not a mismatch
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9717e0bb96fa7463895795405e9cfb39a365b23764bf8d5d58cac31beb6503ef. Chain 2 (Bitcoin): anchored in block 958650 (2026-07-19T03:36:41Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/QZDA81980136.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x596c9ae7555d38ade668c2b261fb6212e3df19b5fe0548f0bf20e944784cb84e. Chain 2 (Bitcoin): anchored in block 956776 (2026-07-05T10:59:37Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/QZDA81980138.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa4b9c8a9740f93e4e171083a74afdd661501a0477c5e3169876c5e012cfa9316. Chain 2 (Bitcoin): anchored in block 958529 (2026-07-18T09:21:41Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/QZDA81980140.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe2efea3d7b85ef8df38d0d8df3e76e5250da933605d941d1ce3da7518ea6458e. Chain 2 (Bitcoin): anchored in block 956856 (2026-07-06T01:25:57Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/QZNWS2227518.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9b389651fb76083f2420cd36df3258d7e18c1cd96cb7cebc4486fc8540fad177. Chain 2 (Bitcoin): anchored in block 959043 (2026-07-21T18:40:26Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/QZTB22297318.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe6330d5f4c350bcf8adfa23da32e9201343a1fdea0098cda45c6e475c7dd1558. Chain 2 (Bitcoin): anchored in block 956826 (2026-07-05T19:27:56Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/QZTAZ2237429.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xddefac38d7216ff91c2c7bd82becdcb84d4e310ee59dcaedc1d4d39e4aff069f. Chain 2 (Bitcoin): anchored in block 958765 (2026-07-19T18:01:47Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/QZTB72282213.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x54552a787273a380ec92501df6d5d957da93f0ee0d497bdfce858fa2245513d8. Chain 2 (Bitcoin): anchored in block 958943 (2026-07-21T00:27:37Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/QZTB72282218.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe6330d5f4c350bcf8adfa23da32e9201343a1fdea0098cda45c6e475c7dd1558. Chain 2 (Bitcoin): anchored in block 956772 (2026-07-05T10:01:46Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/QZTAZ2237429.